2.5. Fabrication of electrospun PCL scaffolds
The PCL pellets were dissolved in a mixture of chloroform and DMF, as a solvent, with a volume ratio of 80:20 to obtain a final concentration of 12% (w/v). To prepare G3-SPIONs suspension in PCL, 0.1 (w/v) of nanoparticles was added to the PCL solution and sonicated to disperse. The electrospinning process was done at a constant flow rate of 0.3 ml/h and the applied voltage of 20 kV. The distance of the needle to the cylinder collector was set at 20 cm. After that, plasma treatment was done to create surface hydrophilicity using a plasma generator (Diener Electronics, Ebhausen, Germany). Surface treatment was performed with radiofrequency power set at 44 kHz and pure oxygen introduction, 0.4 mbar, for 5 minutes.
2.6. Characterizations
TEM analysis of synthesized SPIONs was performed using an FEI Tecnai G2 Spirit TWIN apparatus. The 1 mg/ml aqueous suspension of G3-SPIONs was placed on the carbon‐coated copper grids to evaluate the size and morphology of SPIONs.
The size distribution and the surface charge of magnetic nanoparticles were determined by Zetasizer Nano ZS, Malvern, UK. The synthesized nanoparticles were dispersed in methanol by probe sonication for 10 min and then analyzed by the instrument.
FTIR analysis was used to prove the surface functionalization of SPIONs with APTES and PAMAM dendrimer. For this purpose, a solid powder of nanoparticles was mixed by KBr powder to form a pellet. Infrared spectra profiles were obtained using BOMEM-SRG1100G FTIR spectrophotometer in the range of 400-4000 cm-1 in the transmittance mode at room temperature. The magnetic property of the nanoparticles was evaluated by the Vibrating sample magnetometer (VSM-par155). This assessment was carried out at room temperature under the applied magnetic field of 8 kOe. To evaluate the morphological cues and microstructure of the electrospun nanofibers, the samples were coated with a thin layer of gold using a sputtering machine (Emitech K450X, Ashford, UK). Then, images were observed by scanning electron microscope (AIS2100; Seron Technology, Uiwang-si, Gyeonggi-do, South Korea) with 15 kV accelerating voltage. The mean diameter and standard deviation of the nanofibers were assessed by the image analyzer.